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I got involved lately in an argument with friends about what kind of 
features / evolutions we might want in a divecomp in the near future. 
Not talking about bells and whistles, but about the core function of 
providing an *adequate* decompression profile.

My main grievance was that today's divecomps are purely predictive,
based on apriori models validated on a statistical basis.
Of course, there are some attempts at adaptation: temperature and
estimate of SAC is used to give some penalties - but this not going 
very far. 
The estimation of the air consumption by merely monitoring the tank 
pressure is a practical nonsense (BC / DS inflation, octopus, ...). 
A flowrate sensor in the LP hose between the first and 2nd stage would
be far better, and not that expensive. Standard industrial sensors are 
available...

Anyway, we are still doing a prediction job, just using more parameters.
I would like the computer *I* wear to work on a decompression schedule 
for *me* on *that* dive, not for the general statistical population of 
divers doing the same profile ;-[

The obvious next step would be then to monitor something that would give
a real feedback on how the individual is doing in respect with the 
theorical model. You could then try to adapt some parameter in the model 
based on that feedback. This is rock-bottom engineering in many areas. 
The only slight trouble is to find a meaningful parameter that we *can* 
measure and monitor underwater ...

I guess we cannot miniaturize a doppler equipment yet. 
But maybe something like the N2 % in the skin would be better than nothing.
After all, look at the small sensor that paramedics use to monitor a victim's
vital functions: it's a small clamp at the tip of a finger, and it gives 
the skin O2 saturation (also the pulse rate, and blood pressure I think).
How does it work ?
Anyone knows if that kind of sensor does exist for N2 ? 
Do we have predictions of N2 dissolution in the skin from the current models ?

Philippe.
Dry-footed since early august, following a minor DCS hit. 
Two weeks to go before hitting the water again.


--- philippe.villard@rp*.fr*; 
"The only difference between       | All opinions expressed here are
 men and children is the cost      | my very own and do not (necessarily)
 of their toys".                   | reflect my employer's position.

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